It is known to provide a valve train or valve actuator assembly for an engine such as an internal combustion engine of a vehicle such as a motor vehicle. Typically, the valve train includes one or more valves, a cam shaft having one or more cams, and a tappet contacting each cam and valve. Typically, engine valve actuation is accomplished via the engine-driven camshaft.
It is also known to provide a valve train for an internal combustion engine having a valve with an adjustable stroke or variable lift. In this patent, the adjustment of the stroke or lift of the valve takes place by an eccentric shaft, which displaces the supporting point of a transfer element disposed between each cam and each intake/exhaust valve, in which case the two eccentrics assigned to one cylinder are of a different geometry. The transfer element is formed by a valve lever, which is supported on the eccentric and is actuated by the cam, which valve lever, in turn, acts upon a rocker lever.
One disadvantage of some of these valve trains is that desired phasing is achieved via a camshaft phaser, which is unacceptable for high compression combustion systems, wherein each valve must be capable of having its own specifiable lift and phase setting. Another disadvantage of some of these valve trains is that they do not provide continuously variable valve lift, phasing, and cylinder deactivation. A further disadvantage of some of these valve trains is that they have only one degree-of-freedom control, coupling the lift and phase of the engine valve, and therefore they require an additional phaser for the camshaft.
As a result, it is desirable to provide a valve actuator assembly for an engine that improves valve lift, phasing, and cylinder deactivation. It is also desirable to provide a valve actuator assembly for an engine having more than one degree-of-freedom to allow decoupling of lift and phasing for an engine valve. It is further desirable to provide a valve actuator assembly for an engine that eliminates the use of a phaser for desired phasing of an engine valve. Therefore, there is a need in the art to provide a valve actuator assembly for an engine that meets these desires.